Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data

Abstract

We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR) and GPS measurements to determine the source parameters for the three main shocks of the 2016 Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw 6.1, 5.9, and 6.5, respectively). Our preferred model is consistent with the activation of four main coseismic asperities belonging to the SW dipping normal fault system associated with the Mount Gorzano‐Mount Vettore‐Mount Bove alignment. Additional slip, equivalent to a Mw ~ 6.1–6.2 earthquake, on a secondary (1) NE dipping antithetic fault and/or (2) on a WNW dipping low‐angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event (the Mw 6.5 earthquake). The recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release.

Source Parameters of the 2016–2017 Central Italy Earthquake Sequence from the Sentinel-1, ALOS-2 and GPS Data

“…Our inverted result is consistent with previous studies [2][3][4][5][6][7]. Because the GPS and InSAR data can provide independent constraints on the fault parameters in this study, the location of the fault rupture should be more accurate.…”

“…The predominant slip occurred on the fault with a peak magnitude of 2.5 m at a depth of 0-6 km, which suggests that the rupture reached the surface (Figure 7). The result is consistent with other papers [3,6,7]. …”

“…The total released geodetic moment is approximately 2.16 × 10 18 Nm (Mw 6.2), and the majority of slip occurred on the fault with a peak magnitude of 1.26 m at a depth of 5-6 km ( Figure 3). The best-fitting slip model consists of two distinct slip patches located beneath the two observed lobes of deformation, in agreement with the previous studies [2][3][4][5][6][7]. The average slip errors are approximately 2.6 cm, except for the area down-dip from the left asperity, where the error increases to 14 cm, which can be attributed to reduced measurement constraints.…”

“…There are 106 stations with three-component coseismic offset estimates for the 24 August 2016 Amatrice earthquake [24] and additional 22 stations released by Cheloni et al [7], 127 stations for the 26 October 2016 earthquake [24], 114 stations for the 30 October 2016 earthquake [24] and 4 stations for the 18 January 2017 earthquake [25]. The coseismic measurements were estimated from 3 days of continuous GPS station positions before and after the main shock, and the stations are around the epicentral area (up to 100 km).…”

The research of interrelation between seismic activity and modern vertical movements of the European permanent GNNS-stations

“…We consider only the vertical movement in order to simplify the task of searching for the correlation between generalized seismicity and generalized parameters of the Earth´s motion. The relationship between vertical movements and seismicity has been established long ago (Yokoyama and Nazzaro, 2002;Dambara, 1966;Yurkevich, 1964) and is confirmed by modern technologies, in particular, InSAR, (Jung and Hong, 2017;Lu et al, 2003;Cheloni et al, 2017). Based on GNSS measurements at 33 points, significant differences were defined in the coseismic and post-seismic vertical displacement of the earthquake in Italy on April 6, 2009 (Cenni et al, 2012), and the coseismic displacement of the earthquake on August 24, 2016 in central Italy (Cheloni et al ., 2016), consistent with seismic and geological data.…”